That means that up to half of all food produced for human consumption is thrown away.

It’s obvious that this waste has environmental consequences, because energy is being used but not really producing anything. But according to the McKinsey Global Institute, this energy is adding up. Its 2012 study, entitled Resource Revolution: Meeting the World’s Energy, Materials, Food, and Water Needsnamed food waste as its #3 area of opportunity for reducing energy usage, calculating that in 2010 dollars there is $252 billion from cost-effective reductions in food waste. And this is all in production: the figure does not include waste from consumers. But as McKinsey notes, whereas

the energy efficiency of buildings, the largest opportunity identified in this analysis, attracts many column inches, while other areas such as food waste and improving the yields on large-scale farms receive little attention compared with their potential impact.

If anything, the McKinsey study underestimates the gains from reducing food waste, because it ignores the problem of food waste going into landfills, where it produces methane, a greenhouse gas with eight times the potency of carbon dioxide.

But it isn’t clear how to capture these gains. McKinsey points out — no doubt as a prelude to a pitch to private sector clients — that most businesses don’t even know how much they are wasting. This is one area where governmental regulation might be able to give businesses an incentive to do things that would make sense for their bottom line over the long term, but which they do not do because it is capital intensive in the short term, and requires system-level changes that no one private sector firm can achieve. Resource Revolution says that public sector involvement could be crucial in waste-saving infrastructure and in pooling small firms to invest in capital intensive storage facilities. More straightforward regulation might be necessary in the developed world, where, says McKinsey, “the vast majority of waste occurs in processing, packaging, and distribution.”

Markets don’t seem to be able to do it. Governments seem uninterested. And the public hasn’t awoken yet. That’s a tragedy. Literally.